From ab47adeb1873ba72d9ad2e7bb7cd6a6c94747232 Mon Sep 17 00:00:00 2001
From: Varun Agrawal <varagrawal@gmail.com>
Date: Tue, 31 Dec 2024 20:45:11 -0500
Subject: [PATCH] fix empty keys case

---
 gtsam/discrete/TableFactor.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gtsam/discrete/TableFactor.cpp b/gtsam/discrete/TableFactor.cpp
index 67ba19d39..a833e1c5e 100644
--- a/gtsam/discrete/TableFactor.cpp
+++ b/gtsam/discrete/TableFactor.cpp
@@ -254,7 +254,11 @@ DecisionTreeFactor TableFactor::toDecisionTreeFactor() const {
 
   // If no keys, then return empty DecisionTreeFactor
   if (dkeys.size() == 0) {
-    return DecisionTreeFactor(dkeys, AlgebraicDecisionTree<Key>());
+    AlgebraicDecisionTree<Key> tree;
+    if (sparse_table_.size() != 0) {
+      tree = AlgebraicDecisionTree<Key>(sparse_table_.coeff(0));
+    }
+    return DecisionTreeFactor(dkeys, tree);
   }
 
   std::vector<double> table;